Doors used as replacements or for new construction are conventionally produced of sheet metal. These doors, particularly when used as outside entrances, as opposed to interior doors, preferably have one or more window sections. These window sections are known as lights and are formed in the door. Numerous frame assemblies have been proposed for use as door light frames.
Door light frames conventionally comprise inner and outer half-frames which sandwich a translucent panel therebetween and support the panel within an opening formed in the door. Each half-frame is formed separately and has a plurality of side members defining a close polygon. Usually, the side members of each frame are separately formed and then attached together by welding, for example, U.S. Pat. No.a 3,004,641 to Johnson, or by corner attaching members, for example, U.S. Pat. No. 4,024,691 to Hansen et al. and U.S. Pat. No. 3,949,526 to Sherlock et al. These conventional methods of forming half-frames are difficult, time-consuming and expensive. Additionally, these side frames are relatively weak at their side member connections. When the side members are welded together to form the half-frames, such welding prevents the use of pre-painted metal strips for forming the frames and require finishing operations after the frame is formed.
Another disadvantage of conventional door systems involves the use of differently formed members for the inner and outer half-frames. Manufacturing and assembly costs are significantly increased by using two differently formed half-frames to produce the frame assembly.
Numerous fastener systems have been used to secure the half-frames together and to the door. Arrangements including threaded fasteners are disclosed in U.S. Pat. Nos. 4,430,836 and 4,413,397 to McKann, the subject matter of each patent being incorporated herein by reference. However, these arrangements require the relatively precise relative positioning of the fastener parts or of the holes in the half-frames for the fastener parts. The fastener means are not readily adjustable to permit realignment of the fastener mechanism during assembly. Further, these mechanisms use the fastener mechanism for supporting the frame, which supporting complicates assembly.
Conventional door light frame systems often are difficult to adequately insulate. Thermal insulation can be a significant problem, particularly for metal frames which may readily conduct heat between the inner and outer half-frames.
Some conventional door light frame systems are disadvantageous in that the fastener means are exposed on the outer half-frame. Such exposure requires special treatment to obscure that fastener end, thereby complicating assembly.